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Microorganisms Jan 2023Paracetamol is one of the most used pharmaceuticals worldwide, but due to its widespread use it is detected in various environmental matrices, such as surface and ground...
Paracetamol is one of the most used pharmaceuticals worldwide, but due to its widespread use it is detected in various environmental matrices, such as surface and ground waters, sediments, soils or even plants, where it is introduced mainly from the discharge of wastewater and the use of sewage sludge as fertilizer in agriculture. Its accumulation in certain organisms can induce reproductive, neurotoxic or endocrine disorders, being therefore considered an emerging pollutant. This study reports on the isolation, from sewage sludge produced in wastewater treatment plants (WWTPs), of bacterial strains capable of degrading paracetamol. Up to 17 bacterial strains were isolated, but only two of them, identified as CSW02 and CSW01, were able to degrade very high concentrations of paracetamol in solution as a sole carbon and energy source, and none of them had been previously described as paracetamol degraders. These bacteria showed the ability to degrade up to 500 mg L of paracetamol in only 6 and 4 h, respectively, much quicker than any other paracetamol-degrader strain described in the literature. The two main paracetamol metabolites, 4-aminophenol and hydroquinone, which present high toxicity, were detected during the degradation process, although they disappeared very quickly for paracetamol concentrations up to 500 mg L. The IC of paracetamol for the growth of these two isolates was also calculated, indicating that CSW01 was more tolerant than CSW02 to high concentrations of paracetamol and/or its metabolites in solution, and this is the reason for the much lower paracetamol degradation by CSW02 at 2000-3000 mg L. These findings indicate that both bacteria are very promising candidates for their use in paracetamol bioremediation in water and sewage sludge.
PubMed: 36677487
DOI: 10.3390/microorganisms11010196 -
Ecotoxicology and Environmental Safety Feb 2023Crude oil pollution is environmentally ubiquitous and has become a global public concern about its impact on human health. Asphaltenes are the key components of heavy...
Biodegradation of asphaltenes by an indigenous bioemulsifier-producing Pseudomonas stutzeri YWX-1 from shale oil in the Ordos Basin: Biochemical characterization and complete genome analysis.
Crude oil pollution is environmentally ubiquitous and has become a global public concern about its impact on human health. Asphaltenes are the key components of heavy crude oil (HCO) that are underutilized due to their high viscosity and density, and yet, the associated information about biodegradation is extremely limited in the literature. In the present study, an indigenous bacterium with effective asphaltene-degrading activity was isolated from oil shale and identified as Pseudomonas stutzeri by a polyphasic taxonomic approach, named YWX-1. Supplemented with 75 g L heavy crude oil as the sole carbon source for growth in basic mineral salts liquid medium (MSM), strain YWX-1 was able to remove 49% of asphaletene fractions within 14 days, when it was cultivated with an initial inoculation size of 1%. During the degradation process, the bioemulsifier produced by strain YWX-1 could emulsify HCO obviously into particles, as well as it had the ability to solubilize asphaletenes. The bioemulsifier was identified to be a mixture of polysaccharide and protein through Fourier transform infrared spectroscopy (FT-IR). The genome of strain YWX-1 contains one circular chromosome of 4488441 bp with 63.98% GC content and 4145 protein coding genes without any plasmid. Further genome annotation indicated that strain YWX-1 possesses a serial of genes involved in bio-emulsification and asphaltenes biodegradation. This work suggested that P. stutzeri YWX-1 could be a promising species for bioremediation of HCO and its genome analysis provided insight into the molecular basis of asphaltene biodegradation and bioemulsifier production.
Topics: Humans; Biodegradation, Environmental; Pseudomonas stutzeri; Spectroscopy, Fourier Transform Infrared; Petroleum; Minerals
PubMed: 36669280
DOI: 10.1016/j.ecoenv.2023.114551 -
Microbial Cell Factories Dec 2022Extremolytes enable microbes to withstand even the most extreme conditions in nature. Due to their unique protective properties, the small organic molecules, more and...
BACKGROUND
Extremolytes enable microbes to withstand even the most extreme conditions in nature. Due to their unique protective properties, the small organic molecules, more and more, become high-value active ingredients for the cosmetics and the pharmaceutical industries. While ectoine, the industrial extremolyte flagship, has been successfully commercialized before, an economically viable route to its highly interesting derivative 5-hydroxyectoine (hydroxyectoine) is not existing.
RESULTS
Here, we demonstrate high-level hydroxyectoine production, using metabolically engineered strains of C. glutamicum that express a codon-optimized, heterologous ectD gene, encoding for ectoine hydroxylase, to convert supplemented ectoine in the presence of sucrose as growth substrate into the desired derivative. Fourteen out of sixteen codon-optimized ectD variants from phylogenetically diverse bacterial and archaeal donors enabled hydroxyectoine production, showing the strategy to work almost regardless of the origin of the gene. The genes from Pseudomonas stutzeri (PST) and Mycobacterium smegmatis (MSM) worked best and enabled hydroxyectoine production up to 97% yield. Metabolic analyses revealed high enrichment of the ectoines inside the cells, which, inter alia, reduced the synthesis of other compatible solutes, including proline and trehalose. After further optimization, C. glutamicum Ptuf ectD achieved a titre of 74 g L hydroxyectoine at 70% selectivity within 12 h, using a simple batch process. In a two-step procedure, hydroxyectoine production from ectoine, previously synthesized fermentatively with C. glutamicum ectABC, was successfully achieved without intermediate purification.
CONCLUSIONS
C. glutamicum is a well-known and industrially proven host, allowing the synthesis of commercial products with granted GRAS status, a great benefit for a safe production of hydroxyectoine as active ingredient for cosmetic and pharmaceutical applications. Because ectoine is already available at commercial scale, its use as precursor appears straightforward. In the future, two-step processes might provide hydroxyectoine de novo from sugar.
Topics: Corynebacterium glutamicum; Amino Acids, Diamino; Bacteria
PubMed: 36578077
DOI: 10.1186/s12934-022-02003-z -
IScience Dec 2022Bacteria of the genus consume preferred carbon substrates in nearly reverse order to that of enterobacteria, and this process is controlled by RNA-binding translational...
Bacteria of the genus consume preferred carbon substrates in nearly reverse order to that of enterobacteria, and this process is controlled by RNA-binding translational repressors and regulatory ncRNA antagonists. However, their roles in microbe-plant interactions and the underlying mechanisms remain uncertain. Here we show that root-associated diazotrophic A1501 preferentially catabolizes succinate, followed by the less favorable substrate citrate, and ultimately glucose. Furthermore, the Hfq/Crc/CrcZY regulatory system orchestrates this preference and contributes to optimal nitrogenase activity and efficient root colonization. Hfq has a central role in this regulatory network through different mechanisms of action, including repressing the translation of substrate-specific catabolic genes, activating the nitrogenase gene posttranscriptionally, and exerting a positive effect on the transcription of an exopolysaccharide gene cluster. Our results illustrate an Hfq-mediated mechanism linking carbon metabolism to nitrogen fixation and root colonization, which may confer rhizobacteria competitive advantages in rhizosphere environments.
PubMed: 36505936
DOI: 10.1016/j.isci.2022.105663 -
PloS One 2022Two-component systems (TCSs) are widespread regulatory systems in bacteria, which control cellular functions and play an important role in sensing various external...
Two-component systems (TCSs) are widespread regulatory systems in bacteria, which control cellular functions and play an important role in sensing various external stimuli and regulating gene expression in response to environmental changes. Among the nineteen genes for the two-component system found in the whole genome of Pseudomonas stutzeri LH-42, one of the TCS coded by the HK-1 gene, has a structural domain similar to the HAMP domain, which plays an important role in regulating bacterial virulence in other bacteria. In this study, the deletion mutant LH-42△HK-1 was successfully constructed using the lambda Red recombinase system. Compared with the wild-type strain, the mutant strain LH-42△HK-1 showed a significantly slower growth time and a longer stationary phase time. In addition, in the plate bacteriostatic experiment with Escherichia coli DH5α as an indicator strain, the inhibition zone size of the mutant strain showed significantly less than the wild-type strain(P<0.05), indicating that the virulence of the mutant strain was significantly reduced compared with the wild-type strain. Overall, the results indicate that the deletion of the gene HK-1 decreased bacterial virulence in Pseudomonas stutzeri LH-42.
Topics: Humans; Pseudomonas stutzeri; Virulence; Bone Plates; Escherichia coli; Escherichia coli Infections
PubMed: 36445858
DOI: 10.1371/journal.pone.0277089 -
Environmental Pollution (Barking, Essex... Jan 2023Atmospheric particulate matter (PM) contains a mixture of chemical and biological elements that pose threat to human health by increasing susceptibility to respiratory...
Atmospheric particulate matter (PM) contains a mixture of chemical and biological elements that pose threat to human health by increasing susceptibility to respiratory diseases. Although the identification of the microorganisms composing the PM has been assessed, their immunological impacts are still questionable. Here, we examined the mechanisms responsible for the pathogenicity of Pseudomonas stutzeri PM101005 (PMPS), a bacterium isolated from fine dust, in lung epithelial cells, alveolar cells, and macrophages. Relative to its comparative strain Pseudomonas stutzeri (PS), infections with PMPS induced higher production of inflammatory cytokines and chemokines, mediated by the activation of NF-κB and MAPK signaling pathways. Additionally, with three-dimensional (3D) airway spheroids which mimic the human bronchial epithelium, we confirmed that PMPS infections lead to relatively higher induction of pro-inflammatory cytokines than PM infections. Consistent results were observed in murine models as the infections with PMPS provoked greater inflammatory responses than the infections with PS. These PMPS-induced responses were mediated by the signaling pathways of the Toll-like receptors (TLRs), which regulated PMPS infection and played an important role in the expression of the antibiotic peptide β-defensin 3 (BD3) that suppressed PMPS proliferation. Moreover, PM pretreatment enhanced inflammatory responses and tissue damage of PMPS, while reducing BD3 expression. Overall, these results indicate that PM-isolated PMPS induce TLR-mediated inflammatory responses in lung tissues, and contributes to the understanding of the etiology of PM-induced respiratory damage.
Topics: Mice; Humans; Animals; Particulate Matter; Pseudomonas stutzeri; Lung; Cytokines; Signal Transduction
PubMed: 36435285
DOI: 10.1016/j.envpol.2022.120741 -
Toxins Nov 2022and the produced aflatoxins cause great hazards to food security and human health across all countries. The control of and aflatoxins in grains during storage is of...
and the produced aflatoxins cause great hazards to food security and human health across all countries. The control of and aflatoxins in grains during storage is of great significance to humans. In the current study, bacteria strain YM6 isolated from sea sediment was demonstrated effective in controlling by the production of anti-fungal volatiles. According to morphological characteristics and phylogenetic analysis, strain YM6 was identified as YM6 can produce abundant volatile compounds which could inhibit mycelial growth and conidial germination of . Moreover, it greatly prevented fungal infection and aflatoxin production on maize and peanuts during storage. The inhibition rate was 100%. Scanning electron microscopy further supported that the volatiles could destroy the cell structure of and prevent conidia germination on the grain surface. Gas chromatography/mass spectrometry revealed that dimethyl trisulfide (DMTS) with a relative abundance of 13% is the most abundant fraction in the volatiles from strain YM6. The minimal inhibitory concentration of DMTS to conidia is 200 µL/L (compound volume/airspace volume). Thus, we concluded that YM6 and the produced DMTS showed great inhibition to , which could be considered as effective biocontrol agents in further application.
Topics: Humans; Aspergillus flavus; Aflatoxins; Pseudomonas stutzeri; Phylogeny
PubMed: 36422962
DOI: 10.3390/toxins14110788 -
Journal of Environmental Health Science... Dec 2022A consortium of bacteria capable of decomposing oily hydrocarbons was isolated from tarballs on the beaches of Terengganu, Malaysia, and classified as , , and . The...
UNLABELLED
A consortium of bacteria capable of decomposing oily hydrocarbons was isolated from tarballs on the beaches of Terengganu, Malaysia, and classified as , , and . The Taguchi design was used to optimize the biodegradation of diesel using these bacteria as a consortium. The highest biodegradation of diesel-oil in the experimental tests was 93.6%, and the individual n-alkanes decomposed 87.6-97.6% over 30 days. Optimal settings were inoculum size of 2.5 mL (1.248 OD); 12% (v/v) the initial diesel-oil in a minimal salt medium of pH 7.0, 30.0 gL NaCl and 2.0 gL NHNO concentration, incubated at 42 °C temperature and 150 rpm agitation speed. Parameters significantly improved diesel-oil removal by consortium as shown by the model determination coefficient (R = 90.89%; < 0.001) with a synergistic effect of agitation speed significantly contributing 81.03%. Taguchi design determined the optimal settings for the parameters under study, which significantly improved diesel-oil removal by consortium. This can be used to design a novel bioremediation strategy that can achieve optimal decontamination of oil pollution in a shorter time.
SUPPLEMENTARY INFORMATION
The online version contains supplementary material available at 10.1007/s40201-022-00812-3.
PubMed: 36406595
DOI: 10.1007/s40201-022-00812-3 -
Microorganisms Oct 2022Diazotroph mutants designed using metabolic engineering to excrete surplus ammonium were used to enhance nitrogen fixation and plant growth, as the levels of nitrogen...
Diazotroph mutants designed using metabolic engineering to excrete surplus ammonium were used to enhance nitrogen fixation and plant growth, as the levels of nitrogen fixation attained with diazotrophs are insufficient for the plant's needs. In this study, wild-type (A1501) and engineered ammonium-excreting (1568/pVA3) strains of nitrogen-fixing strains were tested in vitro based on plant growth-promoting traits, such as phosphate solubilization ability, indole acetic acid (IAA) production and nitrogenase activities, as well as ammonium excretion as affected by mannitol-mediated osmotic stress. The maize plant growth-promoting effect of the A1501 and 1568/pVA3 strains was evaluated in pots and in the field, and the N-dilution technique was employed to assess the proportion of plant nitrogen derived from nitrogen fixation. The results demonstrate that the 1568/pVA3 strain displayed higher IAA production and nitrogenase activity than A1501 and released significant quantities of ammonium. After 50 days, in all of the conditions assayed, maize inoculated with 1568/pVA3 accumulated more plant biomass (3.3% on average) and fixed N (39.4% on average) than plants inoculated with A1501. In the field experiment, the grain yield of maize was enhanced by 5.6% or 5.9% due to the inoculation of seeds with 1568/pVA3 in the absence or presence of exogenous N fertilizer, respectively. Therefore, the engineered strain tested in the greenhouse and field was shown to perform better than the wild-type strain with respect to maize growth parameters and biologically fixed nitrogen.
PubMed: 36296262
DOI: 10.3390/microorganisms10101986 -
Microbes and Environments 2022Excess nitrate (NO) and nitrite (NO) in surface waters adversely affect human and environmental health. Bacteria with the ability to remove nitrogen (N) have been...
Excess nitrate (NO) and nitrite (NO) in surface waters adversely affect human and environmental health. Bacteria with the ability to remove nitrogen (N) have been isolated to reduce water pollution caused by the excessive use of N fertilizer. To obtain plant growth-promoting rhizobacteria (PGPR) with salt tolerance and NO-N removal abilities, bacterial strains were isolated from plant rhizosphere soils, their plant growth-promoting effects were evaluated using tomato in plate assays, and their NO-N removal abilities were tested under different salinity, initial pH, carbon source, and agriculture wastewater conditions. The results obtained showed that among the seven strains examined, five significantly increased the dry weight of tomato plants. Two strains, Pseudomonas stutzeri NRCB010 and Bacillus velezensis NRCB026, showed good plant growth-promoting effects, salinity resistance, and NO-N removal abilities. The maximum NO-N removal rates from denitrifying medium were recorded by NRCB010 (90.6%) and NRCB026 (92.0%) at pH 7.0. Higher NO-N removal rates were achieved using glucose or glycerin as the sole carbon source. The total N (TN) removal rates of NRCB010 and NRCB026 were 90.6 and 66.7% in farmland effluents, respectively, and 79.9 and 81.6% in aquaculture water, respectively. These results demonstrate the potential of NRCB010 and NRCB026 in the development of novel biofertilizers and their use in reducing N pollution in water.
Topics: Agriculture; Bacteria; Carbon; Denitrification; Fertilizers; Glucose; Glycerol; Humans; Nitrates; Nitrites; Nitrogen; Nitrogen Dioxide; Soil; Wastewater; Water
PubMed: 36123022
DOI: 10.1264/jsme2.ME22025